The demand for high-capacity wireless services is bringing increasing chall
enges, especially for delivery of the 'last mile'. Terrestrially, the need
for line-of-sight propagation paths represents a constraint unless very lar
ge numbers of base-station masts are deployed, while satellite systems have
capacity limitations. An emerging solution is offered by high-altitude pla
tforms (HAPs) operating in the stratosphere at altitudes of up to 22 km to
provide communication facilities that can exploit the best features of both
terrestrial and satellite schemes. This paper outlines the application and
features of HAPs, and some specific development programmes. Particular con
sideration is given to the use of HAPs for delivery of future broadband wir
eless communications.